I wonder if she has any Latina or Black in her family. That booty is so unlike the normal Asian
It's possible she has some foreign blood, but I doubt it. I'd say it's genetic diversity. Black girls typically have nice butts but I saw a chick today that totally broke that rule. She had a severe case of Noassatall. I think it's big butts are possible with Asians just not common or maybe western diets are influencing their shape. Shiori isn't the only one, take the chick in your sig(albeit fisheyed and photoshopped) Yuu has a nice bubble. I could probably think of a dozen more JAV actresses who have nice butts also. But case and point a real close second to Shiori would be Motozawa Tomomi. But that's just my opinion as chairman
Her next starring release looks like next month from a minor studio. No cover pic yet but the previews are...
She's got a 10 HOUR compilation coming from maguro. Maybe it'll come out in HD